1. Field of the Invention
The present invention relates to portable electronic devices, and more particularly, to a portable electronic device capable of determining an output power of a power adapter to which the portable electronic device is connected and adjusting the system performance of the portable electronic device, and a method for adjusting the system performance of the portable electronic device.
2. Description of the Prior Art
Due to technology development, portable electronic devices are ever-changing. To meet different user needs, portable electronic device manufacturers design portable electronic devices of different models or specifications to provide different performance or function application. Hence, portable electronic devices of different specifications may differ in rated power, which necessitates the use of a power adapter of a corresponding output power. Given the same type of products designed using the same brand, their specification varies from model to model, so does their rated power.
Assuming that a portable electronic device of a high power output, such as a notebook computer, is connected to a power adapter suitable for a low power output, the current outputted from the notebook computer exceeds the maximum current level that can be sustained by the power adapter; as a result, the power adapter executes an over current protection (OCP). To execute the over current protection, the power adapter stops outputting voltage and current temporarily so as to prevent the power adapter from being burnt due to over current, and it is only after a period of time that the power adapter restarts the output of voltage and current, so as to test the status of the notebook computer. The aforesaid period of time is known as a recovering time.
As shown in FIG. 1, to supply power to a portable electronic device through a power adapter connected thereto, the power adapter operates as follows: a power adapter not only boosts the output voltage to a stable level but also executes an over current protection (OCP) by stopping the output of voltage and thus decreasing the output voltage level to zero; after a recovering time t has passed, the power adapter restarts the output of voltage to restore a stable voltage level (in general, the recovering time t is measured in ms); and, if the power adapter still determines that overcurrent persists, the power adapter will enter the over current protection mode again. The power adapter operates in the aforesaid manner repeatedly. As a result, if a user fails to find a power adapter which matches or surpass a portable electronic device, such as a notebook computer, in an output power, the portable electronic device cannot access or receive external power supply, and the portable electronic device may even malfunction or end up with data damage, thereby causing troubles to the user.
A known way of determining the specification of the output of a power adapter involves improving a connection interface between a portable electronic device and the power adapter, disposing additional interface pins for facilitating communication and transmission of signals between the portable electronic device and the power adapter, thereby enabling the portable electronic device to determine the output specification of the power adapter. However, the aforesaid design requires re-designing the structure of the interface between the portable electronic device and the power adapter and the determination mechanism and thereby bringing inconvenience to a manufacturing process and application.